1 Bucharest, 14-16 May 2007 Gerald Duma Central Institute for Meteorology and Geodynamics Vienna, Austria GEOMAGNETIC VARIATIONS AND EARTHQUAKE ACTIVITY 3 rd MagNetE Workshop on European Geomagnetic Repeat Station Survey
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1
Bucharest, 14-16 May 2007
Gerald Duma
Central Institute for Meteorology and Geodynamics
Vienna, Austria
GEOMAGNETIC VARIATIONS AND EARTHQUAKE ACTIVITY
3rd MagNetE Workshopon European Geomagnetic Repeat Station Survey
2
Bucharest, 14-16 May 2007
Observations (1996) – daily range
AUSTRIAM 2.5, 1901-1990
0 2 4 6 8 10 12 14 16 18 20 22 24Local T im e (UTC +1)
02
04
06
0
Nu
mb
er
of
ea
rth
qu
ake
s /
ho
ur
(3 h
r ru
nn
.av.
)
20
77
02
07
80
20
79
02
08
00
Ma
gn
etic
inte
nsi
ty (
nT
)
Sq-variationObs W IK, 1983-85
comp N
GeomagneticObservatory
3
Bucharest, 14-16 May 2007
Duma, Vilardo (INGV),1998
0 2 4 6 8 10 12 14 16 18 20 22 24Local T im e (U TC +1)
01
00
20
03
00
40
0
Str
ain
re
lea
se /
ho
ur
(3 h
r ru
nn
.av.
)
24
39
02
44
00
24
41
02
44
20
Ma
gn
etic
inte
nsi
ty (
nT
)
Sq-variationObs AQU, 1986
comp N
GeomagneticObservatory
Observations (1997) – daily range
Mt. VESUVIUS volcanic eqs, area 10 x 10 km , 1.8 M 3.1,
1972-1996, 1400 events
4
Bucharest, 14-16 May 2007
A seismic daily cycle
Greek philosophers Pliny the Elder, 79 A.D. eruption of
Mt.Vesuvius Conrad, 1932 Shimshoni, 1972 Rarely investigated in recent decades
5
Bucharest, 14-16 May 2007
A seismic daily cycle
0 2 4 6 8 10 12 14 16 18 20 22 24Local T im e (M EZ)
04
81
21
62
0
04
81
21
62
0
04
81
21
62
0
Num
ber
of e
arth
quak
es p
er h
r (3
-hrs
run
n.av
.)
1901-1930
1961-1990
1931-1960
0 2 4 6 8 10 12 14 16 18 20 22 24Local T im e (M EZ)
020
4060
Num
ber
of e
qs p
er
hr
04
812
entireAUSTRIA1901-1990
IMST1997
3 sub-periods 20th centuryAUSTRIAM 2.5
May 31 – June 18, 1997Earthquake swarm in Austria,
region IMST
6
Bucharest, 14-16 May 2007
A seismic daily cycle
Observed also in many other regions
Earthquakes M 5 and 6
A very powerful geodynamic process acting!
7
Bucharest, 14-16 May 2007
GeomagneticObservatory
1880 1900 1920 1940 1960 1980 2000Year
02
46
8
Num
ber
of e
arth
quak
es p
er y
ear
(10
yr r
unn.
av.)
2040
020
650
2090
0
Mag
netic
inte
nsity
(nT
)Obs WIK, comp N
AUSTRIAM 3.1 (Io 5°)
Observations (1996) – long term
8
Bucharest, 14-16 May 2007
Mechanism, models?
Dependence on Local Time Process related to sun A mechanism which penetrates the whole Earth‘s lithosphere Tides ? -> No! High energy mechanism
Can a few nT influence tectonic performance?
9
Bucharest, 14-16 May 2007
The electromagnetic model
Geomagnetic variations reach deep into the Earth‘s interior, 100s and 1000s of km! (magnetotellurics)
Maxwell‘s equations : E - H relation () Earth‘s conductive lithosphere: „telluric currents“ associated with all
geomagnetic variations Applies to all natural variations in a broad
frequency range (from Hz – solar cycle)
10
Bucharest, 14-16 May 2007
The electromagnetic model
Telluric currents and forces
F = e . [ ve . B ]
F ... mechanic force vector
e ... electron charge
ve ... velocity vector
B ... magnetic field vector
‚Lorentz force‘
F
B
ve
e
11
Bucharest, 14-16 May 2007
The electromagnetic model
Magnetic observatories monitor vertical force Fv (t)
M agneticO bservatory
12
Bucharest, 14-16 May 2007
The electromagnetic model
R up ture zone
r
P1
P2
I2 ≠ I1
Regional mechanic moment, torque Tr
13
Bucharest, 14-16 May 2007
A new meaning of variation H
H: monitors change (t) of vertical force Fv in P
gradient H: monitors change (t) of regional mechanic moment Tr ( azimuth Az)
G eogr. Longitude
Geo
gr. L
atitu
de
Seism ic reg ionH(Long,Lat)
grad
ient
H
(directio
n A
z)
Torque
axis
P
14
Bucharest, 14-16 May 2007
Energy – diurnal variation Sq: solar controlled, heating, ionization, tides
(Chapman, Bartels, 1940)
Ionospheric current system (Chapm an, Barte ls, 1940)dayside vortex, N -hemisphere
currents in 1000 Am pere
rot.
10 LT8 LT
6 LT
15
Bucharest, 14-16 May 2007
Energy – diurnal variation
T = MM x H
MMMagnetic Moment
I
Horizontal intensity HEarth’s main field
Ionospheric current system
Lithospheric current systeminduced
A large scale current field, covering 1/3 of the
northern Earth‘s hemisphere
The dayside Sq lithospheric current vortex (Matsushita, 1968)
16
Bucharest, 14-16 May 2007
Energy – diurnal variation
The mechanic moment of Sq for a single loop (Duma, Ruzhin, 2003)
Vsm2Am 11100.89
4)/(DIMM
A 10 10 I current Ring
km 3000 D Diameter
: MM moment Magnetic
0
2
3
Joule VAs 10 26.6 A/m 30 *Vsm )10.(
HMM T
:TTorque
11
11
890
The example demonstrates:
The deformation energy provided to the lithosphere by a single current loop, radius 1500 km and current 10 kA, is equivalent to the energy of an earthquake M 5,1.
50
0
10 kA
1500 km
1000( ca . 1 h r LT )
resistivity:5 * 102 ohmm
current density:2 * 10-8 A/m2
M M ’
17
Bucharest, 14-16 May 2007
Energy – diurnal variation
60% of total moment concentrates in a 30° segment
0
0
0
0
0
0
0.1
0.1
0.1
0.2
0
0
0
0
0
0
0.1
0.1
0.1
0.2
0
0
0
0
0
0.1
0.1
0.1
0.2
0.2
0
0
0
0
0
0.1
0.1
0.1
0.2
0.2
0
0
0
0
0
0.1
0.1
0.1
0.2
0.3
0
0
0
0
0
0.1
0.1
0.2
0.2
0.3
0
0
0
0
0
0.1
0.1
0.2
0.2
0.3
0
0
0
0
0.1
0.1
0.1
0.2
0.3
0.4
0
0
0
0
0.1
0.1
0.2
0.2
0.3
0.4
0
0
0
0
0.1
0.1
0.2
0.3
0.3
0.4
0
0
0
0
0.1
0.1
0.2
0.3
0.4
0.5
0
0
0
0.1
0.1
0.2
0.2
0.3
0.4
0.6
0
0
0
0.1
0.1
0.2
0.3
0.4
0.5
0.6
0
0
0
0.1
0.1
0.2
0.3
0.4
0.6
0.7
0
0
0
0.1
0.2
0.2
0.4
0.5
0.7
0.8
0
0
0
0.1
0.2
0.3
0.4
0.6
0.8
1
0
0
0.1
0.1
0.2
0.3
0.5
0.7
0.9
1.1
0
0
0.1
0.1
0.3
0.4
0.6
0.8
1
1.3
0
0
0.1
0.2
0.3
0.5
0.7
1
1.2
1.5
0
0
0.1
0.2
0.4
0.6
0.9
1.1
1.4
1.7
0
0
0.1
0.3
0.5
0.8
1.1
1.4
1.7
2
0
0.1
0.2
0.4
0.6
1
1.3
1.6
2
2.3
0
0.1
0.2
0.5
0.8
1.2
1.6
2
2.3
2.6
0
0.1
0.3
0.7
1.1
1.5
2
2.4
2.7
3.1
0
0.2
0.5
1
1.5
2
2.4
2.8
3.2
3.5
0
0.3
0.8
1.4
2
2.5
3
3.4
3.7
4
0.1
0.5
1.2
2
2.6
3.2
3.6
4
4.2
4.4
0.2
1
2
2.8
3.5
4
4.3
4.6
4.7
4.9
0.5
2
3.2
4
4.4
4.7
4.9
5.1
5.2
5.2
2
4
4.7
5.1
5.2
5.3
5.4
5.4
5.4
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
2
4
4.7
5.1
5.2
5.3
5.4
5.4
5.4
5.5
0.5
2
3.2
4
4.4
4.7
4.9
5.1
5.2
5.2
0.2
1
2
2.8
3.5
4
4.3
4.6
4.7
4.9
0.1
0.5
1.2
2
2.6
3.2
3.6
4
4.2
4.4
0
0.3
0.8
1.4
2
2.5
3
3.4
3.7
4
0
0.2
0.5
1
1.5
2
2.4
2.8
3.2
3.5
0
0.1
0.3
0.7
1.1
1.5
2
2.4
2.7
3.1
0
0.1
0.2
0.5
0.8
1.2
1.6
2
2.3
2.6
0
0.1
0.2
0.4
0.6
1
1.3
1.6
2
2.3
0
0
0.1
0.3
0.5
0.8
1.1
1.4
1.7
2
0
0
0.1
0.2
0.4
0.6
0.9
1.1
1.4
1.7
0
0
0.1
0.2
0.3
0.5
0.7
1
1.2
1.5
0
0
0.1
0.1
0.3
0.4
0.6
0.8
1
1.3
0
0
0.1
0.1
0.2
0.3
0.5
0.7
0.9
1.1
0
0
0
0.1
0.2
0.3
0.4
0.6
0.8
1
0
0
0
0.1
0.2
0.2
0.4
0.5
0.7
0.8
0
0
0
0.1
0.1
0.2
0.3
0.4
0.6
0.7
0
0
0
0.1
0.1
0.2
0.3
0.4
0.5
0.6
0
0
0
0.1
0.1
0.2
0.2
0.3
0.4
0.6
0
0
0
0
0.1
0.1
0.2
0.3
0.4
0.5
0
0
0
0
0.1
0.1
0.2
0.3
0.3
0.4
0
0
0
0
0.1
0.1
0.2
0.2
0.3
0.4
0
0
0
0
0.1
0.1
0.1
0.2
0.3
0.4
0
0
0
0
0
0.1
0.1
0.2
0.2
0.3
0
0
0
0
0
0.1
0.1
0.2
0.2
0.3
0
0
0
0
0
0.1
0.1
0.1
0.2
0.3
0
0
0
0
0
0.1
0.1
0.1
0.2
0.2
0
0
0
0
0
0.1
0.1
0.1
0.2
0.2
0
0
0
0
0
0
0.1
0.1
0.1
0.2
0
0
0
0
0
0
0.1
0.1
0.1
0.2
-8000 -6000 -4000 -2000 0 2000 4000 6000 8000
1000
2000
km 30
40
50
20
10
0
Geographic latitude
60
Local Time
6 9 12 15 18
H
I
18
Bucharest, 14-16 May 2007
Modelling the electromagnetic effect
Data for H(lat,long) to compute gradient
Hourly values (diurnal variation):
Model simulating Sq telluric current vortex Regional observatory data (average Sq-var.)
Annual values (long term, secular variation):
Retrieved from IGRF, 1900-2010 (grid data) Regional observatory data (annual means, SV)
19
Bucharest, 14-16 May 2007
Case studies – Regions
Austria Taiwan
California Baikal region
20
Bucharest, 14-16 May 2007
Case studies – Austria (M ≥ 3.2, Gradient H – N10W)
Gradient H from IGRF10 (1900-2010)
Diurnal range Long term
0 2 4 6 8 10 12 14 16 18 20 22 24Local T im e (U TC + 1)
11.
21.
41.
61.
82
Mod
el M
SM
- T
OR
QU
E T
(log
ener
gy, r
elat
ive)
-0.0
8-0
.04
00
.04
0.08
log
sei
smic
ene
rgy
/ hou
r(3
-hr
runn
.av.
)
1900 - 2003
1920 1940 1960 1980 2000Y ear
-2.0
-1.8
-1.6
-1.4
-1.2
-1.0
log
sei
smic
ene
rgy
/ yea
r(1
1-yr
run
n.av
.)
0.0
0.2
0.4
0.6
Mod
el M
SM
- T
OR
QU
E T
(log
ener
gy, r
elat
ive)
Gradient H from Sq-Model
21
Bucharest, 14-16 May 2007
Case studies – Taiwan (M ≥ 5, Gradient H – N55E)
Gradient H from IGRF10 (1900-2010)
Diurnal range Long term
Gradient H from Sq-Model
1973 - 1998
0 2 4 6 8 10 12 14 16 18 20 22 24Local T im e (UTC +8)
1.2
1.4
1.6
1.8
22
.2
Mod
el M
SM
- T
OR
QU
E T
(log
ener
gy, r
elat
ive)
0.2
40
.26
0.2
80
.30
.32
0.3
4
log
seis
mic
ene
rgy
/ hou
r(3
-hr
runn
.av.
)
1970 1980 1990 2000 2010Y ear
0.0
0.4
0.8
1.2
1.6
log
seis
mic
ene
rgy
/ ye
ar(5
-yr
runn
.av.
)
-0.6
-0.4
-0.2
00
.2
Mod
el M
SM
- T
OR
QU
E T
(log
en
ergy
, re
lativ
e)
Chi-Chi, 1999
22
Bucharest, 14-16 May 2007
Case studies – Baikal area (M ≥ 5, Gradient H – N00E)
Gradient H from IGRF10 (1900-2010)
Diurnal range Long term
Gradient H from Sq-Model
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
log
sei
smic
ene
rgy
/ ye
ar(5
-yr
run
n.a
v.)
-4-2
02
Mo
de
l MS
M -
TO
RQ
UE
T(l
og
en
erg
y, r
ela
tive
)
1900 1920 1940 1960 1980 2000Y ear
eq-cata logue:U SG S(PD E)
eq-cata logue:SSR
0 2 4 6 8 10 12 14 16 18 20 22 24Local T im e (U TC -7)
1.2
1.4
1.6
1.8
2
Mo
del
MS
M -
TO
RQ
UE
T(l
og
en
erg
y, r
ela
tive
)
-0.1
00
.10
.20
.3
log
se
ism
ic e
ne
rgy
/ ho
ur
(5-h
r ru
nn
.av.
)
eq-cata logue:U SG S(PD E)(2001-2006)
0 2 4 6 8 10 12 14 16 18 20 22 24Local T im e (U TC -7)
0.8
11.
21.
41.
61.
82
Mo
del
MS
M -
TO
RQ
UE
T(l
og
en
erg
y, r
ela
tive
)
0.2
0.25
0.3
0.35
0.4
0.45
log
sei
smic
ene
rgy
/ ho
ur
(5-h
r ru
nn.a
v.)
eq-cata logue:SSR (1900-1980)
1900 - 1980
2001 - 2006
23
Bucharest, 14-16 May 2007
Case studies – California (M ≥ 6, Gradient H – N30E)
Gradient H from IGRF10 (1900-2010)
Diurnal range Long term
Gradient H from Sq-Model
1970 - 2005
0 2 4 6 8 10 12 14 16 18 20 22 24Local T im e (U TC -8) 1
.82
. 02
. 22
.42
.6
Mod
el M
SM
- T
OR
QU
E T
(lo
g en
ergy
, rel
ativ
e)
0.2
0.2
40
.28
0.3
20
.36
log
seis
mic
en
erg
y / h
our
(3-h
r ru
nn.
av.
)
1890 1910 1930 1950 1970 1990 2010Y ear-0
.8-0
.40.
00.
40.
8
log
se
ism
ic e
ne
rgy
/ ye
ar
(9 y
ea
r m
ov.
av.
)
-2.5
-2-1
.5-1
-0.5
00.
5
Mo
de
l SM
S -
TO
RQ
UE
T(l
og
en
erg
y, r
ela
tive
)
24
Bucharest, 14-16 May 2007
Novel aspects
Geomagnetic variations modulate (trigger) seismic activity
Answer to daily rhythm of seismic activity Activity ‚controlled‘ by external sources (sun,
magnetic dynamo) Monitoring: directly by geomagnetic observatories Predictability: systematic diurnal, seasonal, secular
variations (IGRF 2010) Not yet investigated: influence of magnetic storms
25
Bucharest, 14-16 May 2007
Thank your for your attention !
26
Bucharest, 14-16 May 2007
A surprising but plausible model
M agneticO bservatory
Magnetic observatories monitor horizontal force FhC (t)
Z
Earth’s m ainm agnetic field
H
C
G eogr.North time
C
H or . F or ce
F h [I x Z]
CC
Ccu rr. IC
Z
27
Bucharest, 14-16 May 2007
Mt. VESUVIUS – long term volcanic eqs, area 10 x 10 km , 1.8 M 3.1, 1972-1996, 1400 events
Observations – sun spot cycles
Duma, Vilardo (INGV),1998
n: annual number of eqs M 1.8, 1972-1996sf: annual number of solar flares (103)
Duma, Vilardo (INGV),1998
sf
n
1960 1970 1980 1990 2000Year
04
81
2
An
nu
al n
um
ber
of
sola
r fl
ares
(10
3 )
01
00
20
03
00
40
0
An
nu
al n
um
ber
of
eqs
(5 y
r ru
nn
.av.
)
Solar cyclesNo. 20 No. 21 No. 22
28
Bucharest, 14-16 May 2007
ITALY, 4 subregions / IONIAN ILANDS (G4)1910 – 1980, M 5
Observations – daily range
0 2 4 6 8 10 12 14 16 18 20 22 24U TC +1
0
1
2
3
Ho
url
y n
um
be
r o
f ea
rth
qu
ake
s (3
hrs
ru
nn
.av.
)
0 2 4 6 8 10 12 14 16 18 20 22 24U TC +1
0
1
1
2
2
3
Ho
url
y n
um
be
r o
f ea
rth
qu
ake
s (3
hrs
ru
nn
.av.
)
0 2 4 6 8 10 12 14 16 18 20 22 24U TC +1
0
1
1
2
2
3
Ho
url
y n
um
be
r o
f ea
rth
qu
ake
s (3
hrs
ru
nn
.av.
)
I1
I2
I3
0 4 8 12 16 20 24Local Tim e (UTC+1)
0 2 4 6 8 10 12 14 16 18 20 22 24U T C +1
0
0
0
1
1
1
Ho
url
y n
um
be
r o
f ea
rth
qu
ake
s (3
hrs
ru
nn
.av.
)
0 2 4 6 8 10 12 14 16 18 20 22 24U T C +2
0
1
2
3
Ho
url
y n
um
be
r o
f ea
rth
qu
ake
s (3
hrs
ru
nn
.av.
) 0 2 4 6 8 10 12 14 16 18 20 22 24U TC +1
0
2
4
6
8
Ho
url
y n
um
be
r o
f ea
rth
qu
ake
s (3
hrs
ru
nn
.av.
)
I4
all Italy
G4
29
Bucharest, 14-16 May 2007
The regional torque Tr – Energy
> lithosphere block model <
C o n tr ib u tio n o f tw o b lo ck s
j ... C u rren t d en s ity j1 = 0 .6 0 * 1 0 -8 A /m 2 j2 = 0 .4 0 * 1 0 -8 A /m 2
(co rre sp o n d s w ith 5 n T d iffe ren ce H 2 - H 1 )
I1 , I2 ... T o ta l cu rren ts B lo ck 1 , B lo ck 2 I1 = W * T H * j1 = 0 .1 8 0 k A I2 = W * T H * j2 = 0 .1 2 0 k AH ... H o rizo n ta l in ten s ity o f th e E a rth 's m ag n e tic f ie ld H = 3 0 A /mT r ... R eg io n a l to rq u e en e rg y (2 b lo ck s)T r = o * L * (I2 - I1 ) * d * H T r = (4 P i* 1 0 -7 )* (8 * 1 0 5 )* 6 0 * (1 0 6 )* 3 0 T r = 1 8 * 1 0 8 V A s/m (= J o u le )
T h is is th e en erg y eq u a l to a n ea rth q u a k e M 3 .0
I2
I1
H
Fv2
Fv1
TTorque- vector
100 km Block:W =300 kmL =800 kmTH =100 km
Rupture zone
Lithosphere
D istance Bock 1-B lock 2(centers): d = 1000 km
30
Bucharest, 14-16 May 2007
Model of Sq telluric current vortex Fits observed Sq-variations at observatories Computes grad H(LT)
Seism icregion
Sq inducedcurrent vortex
M
P
Q
P
North
East
Surface at P
Seismic region
Curr - E
Cur
r - N
Current I
31
Bucharest, 14-16 May 2007
H – current density
293
6
6
30
/10310
103
/3/103
10;24;10;2
mAE
j
kmmVmVE
mhTnTHTH
E
y
x
y
x
:example) space (half theory neticElectromag
32
Bucharest, 14-16 May 2007
Case studies – Austria (M ≥ 2.5, gradient H – N10W)
Seasonal range, 2001 - 2005
H data from observatories - monthly mean values
33
Bucharest, 14-16 May 2007
Case studies – Austria (M ≥ 2.5, gradient H – N10W)
Seasonal range, 2001 - 2005
Gradient H from observatories - monthly mean values
2002
2001 2003
2004
2001.00 2001.17 2001.34 2001.50 2001.67 2001.84 2002.01M onth
0.00
1.00
2.00
3.00
Num
ber
of e
artq
uake
s / m
onth
(3 m
onth
run
n.av
.)
-0.2
-0.1
0.0
0.1
0.2
Mod
el M
SM
- T
OR
QU
E T
(log
ener
gy, r
elat
ive)
2002.00 2002.17 2002.34 2002.50 2002.67 2002.84 2003.01M onth
0.00
0.40
0.80
1.20
1.60
2.00
Num
ber
of e
artq
uake
s / m
onth
(3 m
onth
run
n.av
.)
-0.3
-0.2
-0.1
0.0
0.1
0.2
Mod
el M
SM
- T
OR
QU
E T
(log
ener
gy, r
elat
ive)
2003.00 2003.17 2003.34 2003.50 2003.67 2003.84 2004.01M onth
0.00
1.00
2.00
3.00
4.00
5.00
Num
ber
of e
artq
uake
s / m
onth
(3 m
onth
run
n.av
.)
-0.1
6-0
.12
-0.0
8-0
.04
0.00
0.0
4
Mod
el M
SM
- T
OR
QU
E T
(log
ener
gy, r
elat
ive)
2004.00 2004.17 2004.34 2004.50 2004.67 2004.84 2005.01M onth
0.00
1.00
2.00
3.00
Num
ber
of e
artq
uake
s / m
onth
(3 m
onth
run
n.av
.)
-0.4
-0.2
0.0
0.2
0.4
Mod
el M
SM
- T
OR
QU
E T
(log
ener
gy, r
elat
ive)
34
Bucharest, 14-16 May 2007
Case studies – Austria (M ≥ 2.5, gradient H – N10W)
Seasonal range, 2001 - 2005
Gradient H from observatories - monthly mean values
2005
2005.00 2005.17 2005.34 2005.50 2005.67 2005.84 2006.01M onth
0.00
1.00
2.00
3.00
Num
ber
of e
arth
quak
es /
mon
th(3
mon
th r
unn.
av.)
-0.4
0.0
0.4
0.8
1.2
Mod
el M
SM
- T
OR
QU
E T
(log
ener
gy, r
elat
ive)
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